1. Field of the Invention
The present invention relates to a navigation device that displays facility marks indicating locations of various facilities superimposed on a map image, and a method for displaying the facility marks on the map image using the same.
2. Description of the Related Art
Generally, a conventional vehicle navigation device is designed to detect a present position of a vehicle, to read out map data corresponding to the present vehicle position from an information recording medium such as a CD or a DVD, and to display a map image covering the present vehicle position and its surroundings on a screen. A vehicle position mark indicating the present vehicle position is also displayed on the screen. The map image covering the surroundings can be scrolled together with the travel of the vehicle with the vehicle position mark at the center thereof.
Almost every vehicle navigation device has a facility mark displaying function of displaying facility marks that indicate locations of facilities such as a convenience store and a gas station, superimposed on the map image. The facility mark displaying function displays on the map image the facility marks corresponding to the facilities that belong to several genres designated by a user as the genres of interest (for example, convenience store, gas station, restaurant, and the like). In a case where the facilities to be displayed are franchised stores, these facility marks each are expressed on the screen with the same trademark as described in signboards commonly used by the facilities. Reference to such facility marks allows the user to obtain information on various kinds of facilities (location, business category, the name of franchisor, and the like).
In the conventional navigation device described above, the smaller value the scaling factor of the map image (reduced scale) has, the more closely the facility marks are positioned with respect to each other. In such a case, the facility marks of interest are densely displayed within the specific display range, and a plurality of facility marks are superimposed on one another, thus making it difficult to grasp the facility information.
Further, in general, the smaller value the scaling factor of the map image has, the greater the number of the facilities arranged within the display range of the map image becomes. For this reason, there are provided a great number of facility marks within the screen, and the ratio of the areas occupied by the facility marks to the entire area of the map image becomes higher, thus making it difficult to view the map image.
As described above, in the conventional navigation device, when superimposing the facility marks on the map image, it is often difficult to grasp the facility information expressed by the facility marks and to view the map image. Therefore, the conventional navigation device does not necessarily have sufficient visibility of the map image including the facility information.
The present invention has been accomplished in view of the above-mentioned technical background, and it is an object of the present invention to provide a navigation device having improved visibility of a map image including the facility information.
To solve the foregoing problems, according to the present invention there is provided a navigation device including a map drawing section for drawing a map image responsive to a predetermined scaling factor, a facility mark drawing section for drawing an image of a facility mark corresponding to a specific facility in a display pattern responsive to the scaling factor, and a display processor for displaying the image of the facility mark drawn by the facility mark drawing section, superimposed on the map image drawn by the map drawing section. In accordance with the present invention, since the image of the facility mark is drawn in the display pattern responsive to the scaling factor of the map image, it is possible to improve the visibility of a map image including the facility information.
Preferably, the facility mark drawing section described above draws the image of the facility mark as a dot image when the value of the scaling factor is a first value or less. Displaying the facility mark by the dot image can make the display area of each facility mark smaller. Thus, even when the value of the scaling factor is set smaller and a great number of facility marks are displayed within the display range of the map image, the ratio of the areas occupied by the facility marks to the entire area of the map image can be restrained to a relatively lesser extent. Accordingly, it is possible to prevent degradation in the visibility of the map image.
The dot image may be drawn in a color corresponding to a genre to which the specific facility belongs. Thus, the genre of the specific facility corresponding to the facility mark can be identified based on the display color.
Further, the navigation device may comprise a dot definition section for setting a relationship between the dot image and the genre of the specific facility corresponding thereto, by a user""s operation. The user can set the relationship between the dot image and the genre of the specific facility freely at will.
The navigation device may also comprise an auxiliary image drawing section for drawing an auxiliary image indicating the relationship between the dot image and the genre of the specific facility corresponding thereto. The display processor displays the auxiliary image drawn by the auxiliary image drawing section together with the map image and the facility mark image on the same screen. This configuration can facilitate understanding the relationship between the dot image and the genre of the specific facility corresponding thereto.
Preferably, when a plurality of the dot images are positioned close to each other on the display screen, the facility mark drawing section integrates the plurality of closely positioned dot images into one dot image and draws the one dot image. Thus, integrating the plurality of closely spaced dot images into the one dot image can decrease the display area occupied by the dot images as the facility mark images more effectively, thereby improving the visibility of the map image.
Further, the navigation device may comprise a dot designating section for designating the specific dot image and a first detailed information drawing section to draw an information image indicating the genre or kind of the specific facility corresponding to the dot image which is designated by the dot designating section, when any one of the dot images is designated by the dot designating section. Thus, it is possible to identify the detailed genre or the kind of the specific facility corresponding to the designated dot image.
The dot designating section may also include a specific key for designating a dot image that is positioned near the present vehicle position or the present position of a cursor. When the specific key is operated, the first detailed information drawing section performs a drawing operation for the nearby dot image. Operating only the specific key is sufficient to perform a display of the information image indicating the detailed genre or the kind of the specific facility corresponding to the nearby dot image, thereby promoting operability of the navigation device.
Preferably, when a value of the scaling factor is a second value or less, and a plurality of the facility marks are positioned close to one another on a display screen, the facility mark drawing section draws a collective-facility-mark indicating a genre to which the plurality of facility marks belong. In a case where the value of the scaling factor (reduced scale) is relatively small, that is, where the map image is displayed in a relatively wide range, so as to search a route, to know the genres of the facilities (for example, convenience store, gas station and the like) is sufficient. Thus, a plurality of facility marks positioned close to each other are integrated into the collective-facility-mark indicating the genre thereof, which is displayed on the display screen. As a result, the plurality of facility marks are not superimposed on one another and are not densely displayed within the small display range, thereby improving the visibility of a map image including the facility information.
Further, in a case where the plurality of facility marks belong to the same genre, the facility mark drawing section preferably performs a drawing operation of the collective-facility-mark when the value of the scaling factor is in a range from a third value, which is larger than the second value, through the second value. Thus, the plurality of facility marks belonging to the same genre are integrated into one collective-facility-mark to be displayed, such that the number of the displayed facility marks can be decreased, whereby the visibility of the map image is improved. The user also can understand easily the locations of the facilities belonging to the desired genre.
Further, when the value of the scaling factor is in a range from a third value, which is larger than the second value, through the second value, the facility mark drawing section may perform a drawing operation of the collective-facility-mark for the plurality of facility marks which belong to the same genre. When the value of the scaling factor is a second value or less, the facility mark drawing section may perform the drawing operation of another collective-facility-mark for the plurality of facility marks which belong to different genres, in addition to the drawing operation of the collective-facility-mark for the facility marks belonging to the same genre. When the value of the scaling factor is much smaller, the display locations of respective facility marks are displayed very close to each other on the display screen. For this reason, the plurality of facility marks belonging to different genres are integrated into another collective-facility-mark, such that the number of facility marks on the display screen can be decreased more effectively, to thereby improve the visibility of the map image.
Preferably, the navigation device further comprises a collective-facility-mark definition section for setting a relationship between the collective-facility-mark and the genres of the specific facilities corresponding thereto by a user""s operation. The user can set the relationship between the collective-facility-mark and the genres of the specific facilities freely at will.
Further, the navigation device may comprise a collective-facility-mark designating section for designating the specific collective-facility-mark, and a second detailed information drawing section to draw an information image indicating the genres or kinds of the specific facilities corresponding to the collective-facility-mark which is designated by the collective-facility-mark designating section, when any one of the collective-facility-marks is designated by the collective-facility-mark designating section. Accordingly, it is possible to designate the desired collective-facility-mark, and to understand the detailed genres or kinds of the plurality of facilities corresponding thereto.
The collective-facility-mark designating section may include a specific key for designating the collective-facility-mark that is positioned near the present vehicle position or the present position of a cursor. When the specific key is operated, the second detailed information drawing section may perform a drawing operation for the nearby collective-facility-mark. Operating only the specific key is sufficient to perform a display of the information image indicating the detailed genres or the kinds of the specific facilities corresponding to the nearby collective-facility-mark, thereby promoting operability of the navigation device.
Preferably, when the value of the scaling factor is greater than the third value, the map drawing section draws an outline of a specific building, and the facility mark drawing section draws the images of the facility marks relating to the building within the outline of the building. For instance, the specific building may be a building including a plurality of facilities to be drawn as facility marks (for example, a building including a convenience store, a restaurant and the like). In a case where the value of the scaling factor is relatively large, that is, in a case where the map image is a wide view, the facility marks are drawn within the outline of the building in a scattered manner, to thereby facilitate understanding the kinds of facilities within the building.
A method for displaying facility marks indicating the locations of various facilities on a map image, using a navigation device that superimposes the facility marks on the map image, in accordance with the present invention, comprises drawing the map image responsive to a predetermined scaling factor, drawing an image of the facility mark corresponding to the specific facility in a display pattern responsive to said scaling factor, and displaying the image of said facility mark, superimposed on said map image. According to the method of the present invention, the image of the facility mark is drawn in the display pattern responsive to the scaling factor of the map image, making it possible to improve the visibility of the map image including the facility information.